are we in agreement that no matter what the fly does the jar weighs the same, as in the glass and lid, THAT weighs the same ( hhehe trick question if worded so in the question )
what we're talking is the flys weight at rest, are the forces it puts out in flght = to it's weight. whos got a set of scales?

has anyone ever jumped in a train wondering if the train will move while your in the air and you land somewhere else??? i have and was disapointed to land in the same spot lol to young to know about momentum, but i'm sure now thats the longest leap i've ever made lol